M5Stack Weight I2C Unit (HX711) - 24-Bit Precision Load Cell Amplifier Module

The default I2C address is 0x26. The address is typically hard-coded in the firmware of the onboard STM32 microcontroller. For most M5Stack units, the address is not user-configurable via jumpers; you would need to modify and reflash the firmware to change it, which requires specific development tools.

Yes, the I2C protocol supports multiple devices on the same bus. Since each unit has a fixed address (0x26), you cannot connect two units with the same address directly. To use multiple identical units, you would need to modify the firmware on each to assign a unique I2C address, or use an I2C multiplexer (like a TCA9548A) to manage them on separate channels.

It is designed for standard 4-wire (or 6-wire with sense) strain gauge load cells (e.g., 5kg, 10kg, 50kg). You connect the load cell's E+, E-, A+, A- wires to the corresponding terminals on the provided VH3.96 connector. The included HY2.0 cable connects the module's I2C and power pins (VCC, GND, SDA, SCL) to your microcontroller.

Yes, calibration is required for accurate weight readings. The process involves taking two known weight measurements (typically zero and a known calibration weight) and using a library function (like the HX711_ADC library for Arduino) to set the calibration factor. The module outputs raw ADC counts, which your code must scale to engineering units (grams, kilograms) based on your specific load cell's rating.

The module's logic (STM32 & I2C) typically operates at 3.3V or 5V, supplied via the VCC pin. The HX711 chip provides the excitation voltage (AVDD) to the load cell, which is usually 5V or 3.3V derived from the same supply. It is crucial to check the load cell's specifications to ensure the excitation voltage is within its rated range, usually 5-10V, but many common cells work with 5V.